lemonadegame

gentlemen,

my motor wouldn't go into 1st and 2nd for a stage. took this to the mechanics, and they tested first if the linkages needed replacing [not sure what these are =\] which they replaced...when that didn't solve the problem they went for a new gearbox. now being an LSD engine, it was a bit hard to find one.

anyways they replaced it, i got a whole new gearbox. now the following is happening:
- speedo doesn't work [this happened shortly after the repair]
- when i get the revs up too high, the car will start shuddering and the revs won't go any further. its semi alright, as this is the point where i pretty much need to change gears [otherwise im over-revving]

my question is, and its a long shot - could they have inadvertedly disconnected something or tampered with anything? also i read about manuals requiring a timing belt replacement every 60,000 km...could this be the shuddering?

i'm grasping at straws, and apologies if im posting in the wrong section. thank you in advance.